eCompass

A compass to keep you on the right track.

🛆 eCompass Chip

An eCompass is a tilt compensated electronic compass utilizing an accelerometer and a magnetometer. Those from ST Microelectronics provide very accurate acceleration and guidance. Having already worked with the LSM303AGR in the past, this is the solution I opted for.

ST's module offers a very low power system for very high performance. Its accelerometer coupled with a magnetometer, all in a 4mm^2 package, makes it a real eye-catcher.

The LSM303AGR is polyvalent: it can detect movement, provide orientation information, assist in dead-reckoning and much more. It's the perfect compass for the project.

Technological Capabilities

CharacteristicDescription

Package

LGA-12 | 2x2x1mm

Acceleration Features

3 axes (X/Y/Z) ±2 / ±4 / ±8 / ±16g selectable full scales Avg of 3.7µA power consumption

Magnetic Features

3 magnetic field channels (X/Y/Z) ±50 gauss magnetic dynamic range Avg of 200µA power consumption

Resolution

16-bit data output

Speed Mode

100kHz, 400kHz, 1MHz, 3.4MHz

Operating Temperature

-40°C ti +85°C

Current consumption in power-down mode

~2µA

🛆 Hardware Integration

To integrate this component, simply refer to the datasheet. Pin n°5 is connected to ground via a 220nF capacitor. The eCompass is supplied in 3.3V with three decoupling capacitors (see page 35 of the datasheet).

Pin NumberSymbolDescription

1

SCL

SPC

I2C serial clock SPI serial port clock

2

CS_ACC

Accelerometer: SPI enable

I2C/SPI mode selection

3

CS_MAG

Magnetometer: SPI enable

I2C/SPI mode selection

4

SDA

SDI

SDO

I2C serial data (SDA)

SPI serial data input (SDI)

3-wire interface serial data output (SDO)

5

C1

Capacitor connection (C1 = 220 nF)

6 & 8

GND

Connected to GND

7

INT_MAG

DRDY

Magnetometer interrupt

Data-ready signal

9

Vdd

Power supply

10

Vdd_IO

Power supply for I/O pins

11

INT_2_XL

Accelerometer interrupt 2

12

INT_1_XL

Accelerometer interrupt 1

🛆 Documentation

PreviousPressureNextRGBW Light

Last updated